If a queen was given the ability to also move as a knight, games would be a lot shorter and complex b/c defending against such a powerful attacking peace would be insanely hard if your opponent knows how to use it.

Major holes would be put in every opening and players would need to change strategies around.

Look at it like adding modern stealth bombers to both sides of WW1 and imagine how much the battlefield would need to change b/c of this new threat.

Please - never give the Queen the power of a Knight, because then it would never be possible to fork the King and the Queen and win the queen. That power alone makes the knight the "Joker of the chess broad."